This invention relates to a tar melting kettle and, more particularly, a kettle having a specially designed top to prevent exposure of the melting tar to atmosphere both upon insertion of extra blocks of tar for melting and in the vent line for the kettle.
Prior to the present invention, any different types of tar melting kettles have been used. Typically, the kettles would have a base frame to which would be attached an axle with wheels located on each end thereof. A draw bar on the front of the base frame would allow the kettle to be easily moved from one location to another. The vat portion of the kettle would be mounted on the base frame with a lid being used to cover the kettle. Normally, the lid would have a handle bar opening from the side to allow the insertion of blocks of tar through the lid into the vat. The vat would be heated by a burner which would have appropriate tubes flowing through the bottom of the kettle to allow flames from the burner to heat the tar. As the tar melts, a pump operated by a motor outside of the vat would pump the tar through the top of the kettle to any desired location.
In the prior kettle just discussed, the lid normally consisted of a reinforced frame which attached to the top of the vat with a special cover being opened by handle from one side. Upon opening the cover, the melted tar inside of the vat is exposed to atmosphere which causes a very foul smell and pollution of the atmosphere. Upon dropping a block of tar into the vat, some of the melted tar would inevitably splash from the vat onto the person inserting the tar. Also, the vat would normally be vented to atmosphere again adding to the foul smell and pollution. Overnight the cover of the kettle would stick causing it to be very hard to open the following day. Many times the vat would have to be heated simply to open the cover even prior to inserting tar for melting.
A typical tar melting kettle is shown in U.S. Pat. No. 3,804,079, a copy of which is enclosed for the Examiner.